On a baking sheet, tear grapes from the stem, and scatter on parchment paper to bake. I roasted approximately 20 grapes.
Tear the green leaves from the cauliflower and cut most of the stem off, but leave some so that it doesn’t crumble when you slice. Starting at the top of the flower, slice down to create disc-like pieces of cauliflower, about ½ inch thick.
On a baking sheet, rub both sides of the cauliflower with olive oil and sprinkle with kosher salt.
Roast grapes and cauliflower at 375-400 degrees for approximately 30-40 minutes, turning the cauliflower once to caramelize each side. The grapes should be slightly caramelized too, and will shrivel up a bit when out of the oven. Grapes contain a lot of sugar, so they can burn easily. If they get too charred for your liking, just soak them in some warm water for a few minutes. They will retain their sweet flavor.
While the cauliflower/grapes are roasting, cook farro in vegetable broth and toast hazelnuts in a small pan. The nuts will be toasted after a minute or two– careful not to burn.
Once the nuts are cooled, place a clean rag over and hit them with a heavy spoon to crack.
Take four large sage leaves and fry them in oil. This takes a few minutes, and the leaves should be crisp (not soft) when you remove.
Pile warm cauliflower, farro and grapes onto plates.
Sprinkle with toasted hazelnuts and crumbled cotija cheese.
Pour dressing liberally over salad and top each plate with a crisp sage leaf or two.